Combine the creamed soup and the cheese soup with the water; heat and stir until smooth. Cook the frozen vegetables as package directs (do not salt). Drain vegetables and add to soups. Add the fish, which has been drained and flaked. Break up potato chips slightly. Reserve 1 1/2 cups. Add the rest to the soup mixture just enough to take up any excess liquid. Taste and adjust seasoning; you may wish to salt slightly. Pour into buttered baking dish. Crush the remaining potato chips to fine crumbs, and sprinkle on top. Bake until hot and bubbly, 20 to 30 minutes.